Enhanced Cu₂S/CdS coaxial nanowire solar cells by piezo-phototronic effect.

Nanowire solar cells are promising candidates for powering nanosystems and flexible electronics. The strain in the nanowires, introduced during growth, device fabrication and/or application, is an important issue for piezoelectric semiconductor (like CdS, ZnO, and CdTe) based photovoltaic. In this work, we demonstrate the first largely enhanced performance of n-CdS/p-Cu(2)S coaxial nanowire photovoltaic (PV) devices using the piezo-phototronics effect when the PV device is subjected to an external strain. Piezo-phototronics effect could control the electron-hole pair generation, transport, separation, and/or recombination, thus enhanced the performance of the PV devices by as high as 70%. This effect offers a new concept for improving solar energy conversation efficiency by designing the orientation of the nanowires and the strain to be purposely introduced in the packaging of the solar cells. This study shed light on the enhanced flexible solar cells for applications in self-powered technology, environmental monitoring, and even defensive technology.